Answers to the Questions A-02

Questions-Answers:

Pharmaceutical Calculation Category:
1. You have a vial of magnesium sulfate solution with concentration of 4.06 mEq/ml. Express this concentration as mg/ml and mOsmol/liter. Molecular weight of magnesium sulfate is 120.

 Solution to the Answers:
A) 4.06mEq/1ml x 120mg/2mEq = 243.6 mg/ml
 B) 243.6mg/1ml x 2mOsmol/120mg x 1,000ml/1L = 4,060mOsmol/L

2. Extra strength Alka-Seltzer effervescent tablets contain 1,985 mg Sodium bicarbonate per tablet. How many millimoles of sodium bicarbonate are obtained in each tablet? Molecular weight of Sodium bicarbonate is 84.

 Solution to the Answers:  
1,985mg/1tablet x 1mmol/84mg = 23.63mmol/tablet

3.Half normal saline is 0.45% sodium chloride. Express this concentration in mEq/ml.

 Solution to the Answers:  
0.45g/100ml x 1,000mg/1g x 1mEq/58.5g = 0.077mEq/ ml

4. Calculate the NaCl equivalent for glycerin, a non-electrolyte with a MW of 92.

 Solution to the Answers:  
i factor for sodium chloride = 1.8
i factor for glycerin = 1.0

58.5/1.8 x 1.0/92 = 0.3533

5. Zinc sulfate is a 2-ion electrolyte, dissociating 40% in weak solutions. Calculate its dissociation factor.

 Solution to the Answers: 
 On the basis of 40% dissociation, 100 particles of zinc sulfate yield:

40 zinc ions
40 sulfate ions
60 undissociated particles
140 total particles